Cray

Seymour Cray
gave a speech in 1974 about his new computer, the
Cray-1.
Around the 13 minute mark, he talks about isolating most of the
processor from the outside memory, and how important that is.
Today that is called a Load/Store Architecture,
and is the primary defining characteristic of
RISC processor design.
The rest of the computer industry didn't realize this until the
late 80s, when
Hennessy
and
Patterson
were beginning to have some success with
MIPS
and
SPARC,
respectively.
(Cray's first load/store machine was the
CDC-6600
introduced in 1964.)

The other thing was keeping the computational sequences, in a
microscopic sense, away from the memory. Providing some intermediate
registers which could be addressed with just a few bits, namely three,
to designate the sources and destinations of operands. That made the
instructions very simple and that thought is still with me, and is
still very present in the machine that I'm designing now. And that is
somewhat unique. Most machines have rather elaborate instruction sets
involving more memory references in the instructions than the machines
that I've designed. So simplicity I guess is a way of saying it. I am
all for simpicity. If it's very complicated I can't understand it. So
that's gotta be the way to go for me.